A new, Phase II version of the NEXCEL active oil management system has been developed by Castrol a BP subsidiary. Integrating a wet sump capability alongside developments in performance, materials and packaging, the Phase II system is ready to help vehicle manufacturers accelerate warm-up times, reduce CO2 emissions, simplify servicing and improve sustainability.
“A further year of development and discussion with vehicle manufacturers has confirmed that the transition to active oil management is inevitable,” states NEXCEL Programme Director Steve Goodier. “Our Phase II system integrates the features the industry has been asking for, taking us to a point where we have a validated solution that is suitable for mass-market applications, complementing our existing dry sump product.”
NEXCEL is a self-contained, sealed cell including the correct grade of oil and specification of filter. Designed for flexible installation anywhere in the engine bay via a docking station intended to provide leak-free instant connection, it is managed by a dedicated electronic control unit that communicates with the vehicle via the standard databus. An electric pump controls the flow of oil between the engine sump and the remote cell and an oil analysis capability can be integrated. Changing the cell takes just 90 seconds.
New wet sump capability
The NEXCEL system was initially validated with Aston Martin in a dry sump application. The Phase II system can be incorporated into a wet sump system, with two integration options: for optimum results, a new sump of smaller capacity is used, with the oil concentrated around the oil pump’s pick-up tube; where the vehicle manufacturer elects to carry over an existing sump, the system can also be integrated e.g. via the drain plug tapping. Smaller sumps are often available from other models using the same engine, so a bespoke pressing may not be required.
Service access to the NEXCEL system is entirely from above, releasing packaging volume protected for a traditional filter and the space required to remove it during servicing. “Space around the block and under the engine is in increasing demand for emissions control systems,” says Goodier. “With NEXCEL, that volume is now available for systems that benefit from close coupling with the engine. We are also talking with vehicle manufacturers who are interested in the possibility of using a bespoke sump to reduce overall engine height.”
Crash-worthiness of the new system has proved to be important. Testing has shown that the NEXCEL system can withstand impacts at 25 g without degradation and 50 g without oil release. Goodier’s team has also validated a range of lower-cost materials suitable for volume production, including manufacturing the oil cells using engineering polymers such as nylon.
Nexcel validates contribution of faster warm-up to CO2 reduction
“Good emissions performance in today’s shorter real-world journeys will also help deliver improved performance in the new WLTP (Worldwide harmonised Light vehicles Test Procedure) test cycles,” adds NEXCEL’s Chief Engineer, Oliver Taylor. “It’s an area we have paid particular attention to in the development of the Phase II system.”
The reduction in warm-up time is achieved by managing the oil volume in the sump. “Every litre of oil removed has a heat capacity equivalent to around 2 kg of aluminium or 4 kg of cast iron,” explains Taylor. “In the new WLTP cycle for passenger cars, around 20 percent of the fuel energy is lost in warming up the metal parts, coolant and oil.”
NEXCEL testing has shown that on a modern 2.0 litre, highly-boosted, direct injection gasoline engine, more than 2.0 litres of oil can be safely removed from the engine oil circuit during most operating conditions, accelerating warm-up and therefore significantly improving emissions and fuel consumption for a majority of journeys.
Taylor believes that the new system will also allow further optimisation of oil specifications, releasing further opportunities for downsizing and friction reduction. “Highly downsized engines place considerable stress on the lubricant, yet oil is the only major engineering component over which the engine designer has no control after the vehicle leaves the factory,” he says. “The sealed nature of the NEXCEL system – which requires an electronic ‘handshake’ when a new cell is fitted – ensures the engine always receives the correct oil, allowing the engine designer to accept more demanding loads and temperatures to increase efficiency further.”
Improved sustainability
Containing the oil within a sealed cell also makes recycling of old oil a much more practical option because it eliminates contamination by other fluids during the drain and recovery operation at garages. NEXCEL units can remain sealed up to the point of re-refining, allowing the oil to be returned to its original specification. For garages, the benefits also include the elimination of spills and greatly simplified oil recovery.
You can follow NEXCEL’s development on LinkedIn, where further technical information is available.
